When a vehicle is operated during blizzard, snow, sleet, or other inclement conditions, precipitation may not be cleared away because the wiper blade becomes lodged with ice and snow build-up, whereupon the blade pushes away from the windshield because of this build-up. The vehicle defroster is incapable of heating the windshield sufficiently to melt the frozen precipitation forming on the blade and its associated mounting and the area to be cleaned. When there is a build-up upon the wiper blade, the wiper blade edge no longer has contact with the windshield. Thus the blade cannot perform the intended function of wiping precipitation from the windshield ultimately severely reducing the vision of the vehicle operator, thereby creating driving hazards which in many instances have resulted in serious accidents.
It has been heretofore proposed that windshield wiper blades and fluid be heated so as to eliminate the hazards noted above. The main object of the present invention is to provide an improved heating means to a windshield wiper blade which incorporates a fluid dispensing arrangement that is particularly designed to be adapted for commercial large scale production. To this end, it is proposed to provide a blade and fluid heating and/or dispensing arrangement which will make maximum use of the electrical energy required for heating the fluid, the blade assembly, and windshield, that is, there will be a far more efficient heating means of the blade and of the windshield traversed by the blade in relation to the amount of electrical energy expended for heating the blade assembly, than has been provided by previous devices conceived for the same purpose. Additionally this invention prevents the accumulation of snow or ice on the windshield.
The wiper blade in which the heating element and fluid dispensing arrangement is incorporated must be constructed of heat resistant material, such as Polymer; so that the material of the blade does not deteriorate in temperatures of up to 220 degrees Fahrenheit; and also incorporate an elongated passageway extending through the central portion of the blade. Such heat resistant blades with elongated passageway are commercially available as "TripleEdge" (U.S. Pat. No. 4,473,919 to Fritz jr. of Oct. 2, 1984) and "Quadrablade" ( Trademark of Lifetime Automotive, PO Box 795428, Dallas, Tex. 75379-5428). The heating element and associated fluid dispensing arrangement of this invention can be inserted within the passageway of said or similar blades. A highly effective heated wiper blade and fluid dispensing arrangement can be created by modifying a new or existing marketed single or multi-edged blade by utilizing applicant's heating element, fluid dispensing arrangement, associated components, and circuitry.
There have been a variety of attempts to improve the wiping action of a windshield wiper to clean the outer surface of a windshield in cold weather.
U.S. Pat. No. 4,152,808 discloses a heating element of 0.125 inch wide and 0.005 inch thick embedded in the sides of a frame adapted to receive a wiper blade. In the upward direction heat is transferred to the frame and linkage elements. In the downward direction, heat is transferred from the element to the frame, from the frame through a gap in the wiper body carrying the blade and finally down to the blade. In the outward lateral direction, heat is transferred to the surrounding air and essentially wasted. This indirect heating method is accordingly inefficient, and limits the flexibility of the blade, thereby inhibiting the blade wiping action.
U.S. Pat. No. 4,360,941 discloses a second, rather complex windshield wiper assembly which incorporates a weather protective hood utilizing electrical conductors affixed on the outer wall of the hood and other conductors affixed on the inner wall of the hood to heat the hood and frame to prevent the accumulation of ice.
U.S. Pat. No. 2,194,6771 discloses a heating means wound around a fibrous core along with an asbestos covering which are fixed and bound together and placed with the wiper tube with no space between components. The heating means is dependent on a fibrous core member and an asbestos sheath. Because of the dependent nature of the heating wire, flexibility is very limited.
U.S. Pat. No. 5,325,561 discloses an unnecessarily complex and inefficient circuitry system. The heating element consists of straight wire which is less than 1/3 of the width of the passageway. Thus the heating element can lie on the passageway causing hot spots and decreasing efficiency and causing blade damage. A thin straight wire has greater probability of breakage or failure. There are several resistors wired in parallel which create substantial heat loss to the overall circuitry. A solution as to how to cope with these very hot resistors is not discussed. This invention teaches the use of multiple connectors which appear to be very prone to damage and disconnection from normal usage and daily occurrences. This invention does not provide sufficient heat to melt ice and snow build-up on the wiper blade in adverse weather conditions without the addition of a protective cover to trap the heat. Such a protective cover can lead to the retention of condensation which can cause rapid deterioration of the blade holder and associated components. The path through which the resistance wire travels and its various connections is quite complex in order to provide the blade with heat.
U.S. Pat No. 5,426,814 discloses a wiper blade with a helical heating arrangement which is in direct contact with the interior blade surface dispensing fluid arrangement; and an air expansion system to fracture ice present on the wiper blade. This invention teaches that the blade can be constructed of material such as natural rubber. This invention does not provide sufficient heat to melt ice build-up on the wiper blade without an air expansion system to fracture ice present on the wiper blade.
The devices disclosed in the aforementioned patents leave much to be desired from the standpoint of simplicity of construction or are not sufficiently flexible to be used with windshields of any desired lateral or longitudinal curvature; some heating element designs cause extremely localized heating which places undue thermal stress on the material of the blade. Some require specialized wiper blade frames and/or wiper arm assemblies. Most prior art does not disclose a solution for preventing and eliminating ice and snow build-up on the wiper blade and associated assemblies and the windshield.
Accordingly, it is an object of the present invention to provide a simple, low cost wiper blade heating and fluid dispensing arrangement which is capable of removing and/or preventing ice or snow build-up, road film and dirt on the wiper blade and associated assemblies and the windshield. It is a further object of this invention to provide a flexible wiper blade heating element and heated fluid dispensing arrangement suitable for incorporation into new or existing wiper blades and associated assemblies; which is not fatigued by the repeated stresses of reciprocation; easy to replace and install; able to adapt to use on windshields having most any lateral or longitudinal curvature
It is yet a further object of this invention to provide a wiper blade heating and heated fluid dispensing arrangement which permits the wiper blade to conform to the shape of the windshield under snow, sleet and all other conditions. Thus providing satisfactory wiping performance while simultaneously removing and keeping the wiper blade, frame, linkage, and windshield free from interference by ice, snow, road film and dirt.
Another object is to provide a wiper blade, fluid reservoir, heating and fluid dispensing arrangement which allows for each 12 Volt blade to be calibrated so as to eliminate complexity, multiple connectors, timer, thermostat, and resistors by designing the heating wire to serve as the heating element, resistor, and incorporating a heated fluid chamber and dispensing means within this arrangement for immediate fluid use.
It is to be understood that this invention is not limited in its application to the details of construction and to the following description or illustrations in the drawings. This invention is capable of other embodiments and of being practiced and carried out in various ways, also. It is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.